In order to write data to media, a write head is typically used. Such a write head is generally part of a merged head that includes a head for writing and a head for reading data from the media. FIG. 1 depicts a side view of a portion of a merged head including a conventional recording head 10 and a conventional read head 30. The conventional recording head 10 includes a conventional first pole (P1) 12 and a conventional second pole (P2) 20 that are separated at the front, near the air-bearing surface, by a conventional write gap 18. Also shown is the hardbake photoresist layer 22 that is typically photoresist that is used to insulate the coils 16 of the conventional write head 10. The conventional P112 includes a conventional pedestal 14. The conventional read head 30 includes first shield (S1) 32, read sensor 34 and second shield 36. The conventional P112 typically lies above S2 and is separated from S2 by a gap 38.
Although the conventional recording head 10 functions, one of ordinary skill in the art will readily recognize that the conventional recording head 10 has a number of drawbacks. These drawbacks particularly impact recording at high areal densities. The conventional pedestal 14 is typically electroplated. In order to fabricate the conventional pedestal 14, a magnetic material is plated, then planarized typically using a chemical mechanical polish (CMP). As a result, for a conventional pedestal 14 having a thickness of approximately three microns, four microns of magnetic material are plated. Furthermore, it is typically desirable for a pedestal to have a relatively short throat height. The throat height is the distance at which the poles begin to diverge from the write gap 18. In the conventional recording head 10, the throat height is given by the width, t, of the conventional pedestal 14. A smaller throat height is desirable to concentrate magnetic flux in the area of the write gap 14. Thus, a smaller throat height for the conventional pedestal 14 is desired because the efficiency of writing would improve. However, the large thickness of material that is electroplated makes it difficult to reduce the throat height. In addition, if the throat height of the conventional pedestal 14 is too small, the conventional pedestal 14 may saturate. As a result, the conventional recording head 10 may experience side erasure, thereby inadvertently writing to adjacent tracks.
In addition, the conventional poles 12 and 20 are subject to pole tip protrusion. The conventional pedestal 14 and the conventional P220 have a coefficient thermal expansion that is widely different from the coefficient of thermal expansion of the write gap 18 and the hardbake photoresist layer 22. During operation, the conventional recording head 22 may experience heating. As a result, different portions of the conventional recording head 10 expand different amounts, causing the write head 10 to distort. The P112 and P220, as well as the hard baked photoresist 22, have large positive coefficients of thermal expansion. As result, the tips of P112 and P220 near the air-bearing surface expand and protrude outward. Moreover, the currents in the conventional write head 10 cause greater local heating in the region of the poles, exacerbating the protrusion of the poles P112 and P220.
The topography of the conventional recording head 10 also makes fabrication of the P220 problematic. Because of the structures fabricated under the P220, the surface on which the P220 is to be fabricated is not flat. Variations in the topography underlying the P220 can cause reflections during photolithography. As a result, the control of the track width of P220 (the dimension of P220 perpendicular to the page in FIG. 1), suffers.
Accordingly, what is needed is a system and method for providing an improved recording head. The present invention addresses such a need.